My invention relates in general to drives and more particularly to stepless, variable ratio drives employing a variable stroke mechanism.
An important advance in the use of variable stroke drives for automatic transmissions was the Waddington drive described in U.S. Pat. Nos. 3,803,932 and 3,874,253, and in pending U.S. patent application Ser. No. 737,632. The Waddington drive of these earlier descriptions employed a cam which rotated at the input speed to the drive and which was automatically controlled to assume various eccentricities relative to the center of input rotation in order to vary the stroke and thereby the torque ratio of the drive. The instant invention also utilizes a variable stroke drive, but has the feature of a nonrotating cam which allows manual control of the cam eccentricity to regulate the stroke and torque ratio of the drive. The manual control capability is desirable in some situations as, for example, when the drive is used for a bicycle transmission. The manual control would accommodate cyclists who would prefer to manipulate the control themselves to suit their particular needs. Indeed the drive is particularly attractive for use as a bicycle transmission because of its compactness, light weight, moderate cost and immediate adaptability to existing bicycle frames. The earlier Waddington drives were either somewhat heavier because they operated at slow input speed and utilized large overrunning clutches, or required some modification to the standard bicycle frame to incorporate an input speed stepup mechanism.